


Dirty Little Secret

by orphan_account



Category: Gravity Falls
Genre: Light Dom/sub, Masturbation, Other, im fucked up im sorry mom, literally id say im going 2 hell but im already there, mind-meld sex, pretty much bill half-possesses dipper as he masturbates, sinning
Language: English
Status: Completed
Published: 2015-08-04
Updated: 2015-08-04
Packaged: 2018-04-13 00:36:47
Rating: Mature
Warnings: Underage
Chapters: 1
Words: 1,800
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4501056
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/orphan_account
Summary: <blockquote class="userstuff">
              <p>Dipper really wants to get off, but when Bill pops up, things get a little bit weird.</p>
            </blockquote>





	Dirty Little Secret

**Author's Note:**

> sorry mom
> 
> Really, though. This popped into my head, and I'm sorry.

Dipper was in a bit of a predicament. While he loved doing stuff with his sister and grunkle, he had no alone time. It definitely didn't help that he shared a room with Mabel; everything was out in the open for the other to see. There was no place he could go to get off, except the bathroom. And while he was sure no one knew what he was doing in there for ten or fifteen minutes at a time, he was still paranoid about someone walking in. It sure as hell wasn't comfortable or even a very good stress relief- he was constantly worried throughout the entire ordeal.

Still, it was the best that he could do, to lay in the tub or slouch on the toilet to take care of it.

He sighed, allowing himself to settle into the curve of the tub, just letting his mind wander to the curves of ladies and hypnotizing movements, intricate dances that ensnared the senses. It wasn't exactly difficult to get a reaction. He didn't quite touch yet, he wanted to think up a fantasy first, something he could actually get into.

As he was thinking, he was completely unaware of the presence slowly creeping itself in, the colors drifting and fading away, with only one yellow triangle floating above the tub. Dipper finally reached for himself, pleased at the mental play he'd concocted.

"Hey, Pine Tree," Bill near-shouted. "Whatcha doin'?"

Dipper nearly jumped out of his skin, (and nearly did jump out of the tub.)

"What are you doing here, man? I'm kind of in the middle of something!" Dipper slouched, trying to hide the obvious boner underneath his boxers.

"I just decided to pop in and see what my least favorite runt was up to, but you're doing something I've never seen before and I wanna know what it is."

Dipper sighed, annoyed beyond all else. "Look, man," he said, shifting, "it's not something people show off or talk about, so just go away."

"But I wanna know," the triangle growled, glaring down. He'd witnessed the rise and fall of thousands of empires, the construction of entire universes (and created a few of his own,) but he had no idea what Dipper was doing, and he despised not knowing something that he was obviously trying to hide.

"Do you really not know?" Dipper asked, resigning himself to another evening of Bill's antics.

"Know what?"

"What I'm doing?"

"What ARE you doing?"

Dipper resisted the urge to throw his hands up in frustration. "I'm masturbating, okay? Jerking off, the one man parade, the single man's date night?"

"What does that mean though?"

"Oh my god..."

"This has something to do with your gods?"

"No, no... Uh... Humans experience, er, hormonal... stuff, and so they... take care of the urges by themselves if they don't have anyone to take care of them with."

"That sounds boring. Why don't you just ignore it and get on with your lives?"

"It's not... It's just... It feels good, okay? Now can you leave me alone?"

Bill moved so that he hovered in front of Dipper's face. "But why does it feel good? Why don't you just not do it, instead? It'd be a whole lot easier if you didn't have to go through all these shenanigans about it."

"I don't know, man. Now can you leave? I was in the middle of something."

"Why don't I merge with you so I can understand?"

"What? You wanna take over my body so you can masturbate with it? Gross, man, get out of here!" Dipper made to push Bill away, but he didn't budge.

"I can be in your body with you controlling it, you know. I could feel everything you feel, but you'd be in control."

"What, and just get off with me? That's super weird, man. Why don't you just go?"

"I'm serious. You'd get to, how did you say it, jerk off, and I'd get to learn about humans. As a bonus, I'll even let you push me out whenever you want. What do you say, Pine Tree, do we have a deal?" Bill extended his hand, waiting for him to take it.

Dipper sighed, caving, "Anything to get you outta here," and shook the proffered appendage.

Immediately Bill's image disappeared, fading into thin air, and Dipper nearly slammed backward into the tub with the force of it. His head felt slightly swollen, like too much of something had been stuffed inside his head.

"Wow, that is really persistent," Bill's voice sounded softly from the back of Dipper's head. "Make it go away, I don't like it."

"What?"

"That thing between your legs. It's demanding attention. Make it stop."

Dipper sighed, laying himself back down into the tub. "That's a boner, dude, now shut up or leave."

"Fine," Bill grumbled.

Dipper closed his eyes and had to think of a new fantasy, one that hadn't been tainted by Bill's arrival. Finally settling on one, he let it play out, eyes still closed.

"Why are those things on their chests exposed? I thought humans covered those. Why are they dancing? Is it some sort of mating call? Why are they moving their hips like that?"

"Bill I swear to god if you don't shut up and let me do this, I'm kicking you out of here. It's weird enough as it is, I don't need you asking questions about every detail."

"Okay, okay, pardon me for trying to learn."

Dipper squeezed his eyes shut again, trying to focus on the imagined movements of pretty girls and allowing his hand to move downward. It landed on his cock, just resting gently on top to provide some pressure. Slowly, took the shaft in his hand, again just applying light pressure. Squeezing the smallest amount, he gave it a little stroke.

Bill made a sound like the mix between a sigh and a groan, then immediately asked, "What the hell was THAT?"

Dipper sighed for the fifth time. "That's part of it, Bill. Do you want to leave or what?"

"Do it again," Bill ordered.

Dipper did, running his hand from the base of his cock to the tip, shuddering a little.

"Sweet Krebnar," came the shaky reply. "Do it again!"

"Bill, this is supposed to be me doing it!"

"Oh come on, I know you like being told what to do. I can feel everything you feel, remember?"

"Yeah, but that doesn't mean that I actually want you to do that, dude. Just... Shut up, okay?"

"Eeeehhhhh, I don't think I will, Pine Tree. You definitely like being bossed around. It's one of your whatshamacallits, uh, a kink! Yeah, it's one of your kinks, Pine Tree, and since it gets you off, I get to feel it."

"You've only felt me do one thing so far."

"You can do MORE than that?!"

Dipper let out an exasperated groan.

"Yeah, Bill, I can do more than one thing. Let me have five minutes, for Christ's sake."

"Fine. Just make it a quick five minu-uhh-uhhhh-hhhh..."

Dipper had cut him off by rubbing a thumb over the head of his cock and stroking it down. Bill tried to interrupt again, but Dipper spat into his palm and twisted the saliva onto the head and spread it down the entire length, making fast little strokes upward. To keep Bill shut up- or at least reduced to mentally panting and groaning- Dipper kept up a constant barrage of masturbatory tricks, from cupping his balls and stroking upwards to gently twisting his palm around the head and giving hard strokes to the base of his dick. By the time five minutes was up, he was a panting, sweaty mess that had to hold back his own moans lest he alert anyone to his actions.

"Okay, Bill," he panted under his breath, a blush covering his face and upper chest, "five minutes is over. What do you want me to do?"

Bill took a moment to collect himself. He hadn't expected things to get quite so... vivid.

"Alright kid, take your hand and put it- ah, just there. Press on it some, harder... Good, good. Now take your other hand, and put it a little higher and move it up and down real fast- unh, just like that, good boy..."

Dipper paused, blushing all the way down to his bellybutton. "Wh-what did you say?"

"Huh? Oh, yeah. That's what you like to hear, right?"

"Y-yeah... I just... didn't expect that."

"Do you want me to not say that?"

"No, no, it's... it's good."

Bill continued on, instructing Dipper and praising him when he did exactly as he said. It wasn't long until they were nearing climax.

"Bill, Bill," Dipper keened softly, "I-I'm gonna..."

It was all Bill could do to groan out any form of response. There was this odd feeling, almost like Dipper's body was tightening, preparing for... something.

And it was. There was an incredible moment of tightness and heat and this incredible elation, almost as if they were moving at great speed. It was exhilarating, a revelation, pure ecstasy, and it was entirely exhausting.

For a moment they both sat there, limp and panting and sweating, enjoying the aftermath.

Eventually, though, they had to deal with what came next: clean up. Dipper was blushing and trying not to think about what exactly he was cleaning up, which if course made Bill more intent on figuring it out.

"But what is it?"

"Doesn't matter."

"Why'd it come out of us?"

"It just does. And it's not us, it's me. Are you gonna leave now or what man?"

"Nah, I wanna know what it is."

"God, it's semen, okay? Jesus, shut up about it already."

"Why'd it come out, though?"

"It helps make babies, Bill, now shut up."

"I wonder if it's the same for Mabel. Doesn't she have a different thingy than you?"

"No, Bill! You have to promise me you won't talk to anyone about this, okay? It's not- It's not something that people talk about, especially with siblings. You got it?"

"Why, though?"

"It just is! Promise me you won't talk about this with anybody?"

"Alright, Pine Tree, I won't. I promise."

"We cool, man?"

"Yeah, we're ice cold. Seriously, put your shorts on."

Dipper complied, pausing once his trousers were buttoned and zipped.

"Hey, Bill?"

"Yeah, kid?"

"Thanks."

"Thanks? For what?"

"For, I don't know... Just, thanks."

"No problem, kiddo. Hey, I'm gonna go. There's some kid summoning me. Great session and all that, but duty calls, you know?"

"Yeah."

"Toodles, Pine Tree!"

And Dipper felt everything regain itself, his head thinning out and feeling normal-sized again. Bill was gone, off to run some demon errand. Dipper definitely did not want to try this again soon at all.


End file.
